Fluid-actuated double acting pump apparatus



April 1962 J. H. ZILLMAN ETAL 3,027,849

I FLUID-ACTUATED DOUBLE ACTING PUMP APPARATUS 6 Sheets-Sheet 1 LPEIMEMOVEE P Original Filed Dec. 27, 1956 To5wm 1 AA TEEN/1702' ACONTEOLLEE -C MOTQQ i 15 ALTERNAT- /N V01 To 25 To MoToq PUMP LAIHJJJT 11 I u I I I II April 3, 1962 J. H. ZILLMAN ETAL 3, 7,

FLUID-ACTUATED DOUBLE ACTING PUMP APPARATUS 6 Sheets-Sheet 2 OriginalFiled Dec. 27, 1956 OM52 MILL/AM! .f/me

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April 3, 1962 J. H. ZlLLMAN ETAL 3,027,849

FLUID-ACTUATED DOUBLE ACTING PUMP APPARATUS 6 Sheets-Sheet 3 5 N M uAZQMM/ mmmm 5 -MGWAMI. M MZfi. 9, e WHW F m A Ja BYW \[IIII Ermn m Ir:

April 3, 1962 J. H. ZILLMAN ETAL 3,027,849

FLUID-ACTUATED DOUBLE ACTING PUMP APPARATUS UPPER n M 2 5 00122 8 DD 284All/5mg;

m 1 Z/LLMA/V April 3, 1962 J. H. ZILLMAN ETAL 3,027,849

FLUID-ACTUATED DOUBLE ACTING PUMP APPARATUS 6 Sheets-Sheet 6 OriginalFiled Dec. 27, 1956 Emw mm? 5 5% J a M U M mm 4 f a m [a 1 m 5 2m 3 5/TO PRODUCTION COLUMN 279 232 $4 274 FROM LOWER BLADDER.

8.11 t 2 FRO M U PPER BLA DDEE 24 COLUMN TO PRODUCTION DOUBLE Poll AM- OERATED REVERSING TIMER MOTOR RE VERSING SWITCH N 1 M? Z Whammy m WNK 4 MNN. fzdm w Unite The present invention relates generally to pumpingapparatus and more particularly to a novel and improved fluid-actuateddouble acting pump that is especially adapted for well pumping. This isa division of our copending application entitled Fluid-Actuated DoubleActing Pump Apparatus, filed December 27, 1956,- Serial No. 630,973, nowPatent No. 2,961,966.

Oil is most often produced from a non-flowing oil Well a by means of asucker rod-operated reciprocating pump. This type of pump employs 'apiston and cylinder adjacent the production Zone of the well andconnected to a surface located source of power by a string of suckerrods. The many disadvantages inherent to the use of the suckerrod-operated reciprocating pumps are familiar to those skilled in theart.

It is a major object of the present invention to provide apositively-acting displacement pump which eliminates thesedisadvantages.

It is a more particular object of the invention to provide a well pumphaving two pumping chambers which receive the liquid to be pumped, thesepumping chambers each housing a bladder element which is alternately eX-panded and contracted so as to force the liquid to be pumped out of thepumping chambers into passages which lead to the top of the well.

Another object is to provide pumping apparatus of the aforedescribednature employing a reversible electric motor coupled to a reversiblepump, the motor operating in one direction until the pump has filled thefirst bladder and then in the opposite direction until the secondbladder has been filled so as to pump a substantially continuous fiow ofoil to the earths surface.

Another object is to provide pump apparatus of the aforedescribed natureincorporating unique means for timing the length of rotation of theelectric motor in a given direction, so as to obtain maximum operatingefiiciency of the unit. 7

It is a further object of the present invention to pro vide pumpingapparatus of the aforedescribed nature having means for preventing theinternal pressurization of the bladders above a predetermined pressure.This feature contributes to a long and trouble-free service life for theapparatus.

It is yet another object of the invention to provide pumping apparatusof the aforedcscribed nature wherein the fluid employed to operate thebladders is completely isolated from the well fluid being pumped.Accordingly, the internal operating parts of the pump are maintainedfree of foreign Wear-inducing substances.

An important object of the invention is to provide pumping apparatus ofthe aforedescribed nature wherein the electric motor is operated in afirst direction until the first bladder is filler with operating fluidto a predetermined pressure whereafter novel sensing means incorpo-Patent 3,027,849 Patented Apr. 3, 1962 rated in the pumping apparatusautomatically effects the reversal of the electric motor so as to effectthe collapse of the first bladder and the filling of the second bladderto a predetermined pressure.

Another object is to provide pumping apparatus of the nature set forthin the paragraph set forth immediately hereinbefore wherein said sensingmeans is sensitive to the amount of energy required to operate saidelectric motor.

It is 'an additional object to provide pumping apparatus of theaforedescribed nature which is embodied in an elongated slenderstructure that may be lowered into a well of relatively small diameter.

It is yet an additional object of the invention to provide an improvedelectrical switching system.

Still a further object is to provide an electrical switching systemwherein an electrical current is substantially reduced prior to beinginterrupted. I

One additional object is to provide an electrical switching system whichwhen activated reduces current flow then performs a switching operationat a point remote from the point of activation.

These and other objects and advantages of the present invention willbecome apparent from the following de tailed description when taken inconjunction with the appended drawings, wherein:

FIGURE 1 is an elevational view taken partly in central vertical sectionshowing a preferred form of pumping apparatus embodying the presentinvention;

FIGURE 2a is an enlarged central vertical sectional view of thedouble-acting pumping unit utilized with said pump apparatus;

FIGURE 2b is a downward continuation of FIGURE 2a;

bFIGURE 2c is a downward continuation of FIGURE 2 FIGURE 3 is a verticalsectional view taken 3--3 of FIGURE 2a;

FIGURE 4 is a horizontal sectional view taken on line '44 of FIGURE 3;

FIGURE 5 is a vertical sectional view taken along line 55 of FIGURE 4;

FIGURE 6 is a horizontal sectional view taken on line 6-6 of FIGURE 2a;

' FIGURE 7 is a horizontal sectional view taken on line 7-7 of FIGURE2a;

FIGURE 8 is a horizontal sectional view taken on line 8-8 of FIGURE 2b;

FIGURE 8a is a horizontal sectional view similar to FIGURE 8, butshowing the parts thereof disposed in a different operating position;

FIGURE 9 is a horizontal sectional view taken on line 9-9 of FIGURE 2b;

FIGURE 10 is a horizontal sectional view similar to FIGURE 8 but showingthe parts thereof disposed in a different operating position;

FIGURE 11 is an enlarged horizontal view taken on line 1111 of FIGURE2b;

FIGURE 12 is an enlarged fragmentary view of the encircled areadesignated 12 in FIGURE 20;

FIGURE 13 shows an electrical circuit which may be utilized with saidpump apparatus;

FIGURES 14, 14a and 14b ShOW a second form of electrical circuit whichmay be employed with said pump apparatus; v

FIGURE 15 shows a third form of electrical circuit that may be employedwith said pump apparatus; and

on line 3 FIGURE 16 shows a fourth form of electrical circuit which maybe employed with said pump apparatus.

General Arrangement The preferred form of pumping apparatus embodyingthe present invention is adapted to be lowered into a well 20 by meansof a string of tubing 21 which also has the purpose of conveying thepumped well fluid, as for example oil, to the top of the well. Thepumping apparatus includes an elongated tubular housing 22 which issecured to the lower end of the tubing string 21 in a conventionalmanner. The housing 22 encloses an upper pumping section U and a similarlower pumping section L. The upper pumping section is formed with apumping chamber 24 while the lower pumping section L is formed with asimilar pumping chamber 26. An upper eXpansible-contractile member, suchas a bladder formed of oil-resistant synthetic rubber 28, operates inthe upper pumping chamber 24 while a similar expansible-contractilemember 30 operates in the lower pumping chamber 26. The upper and lowerpumping chambers are provided with inwardly-opening upper and lowerinlet valves 32 and 34, respectively, for admitting production or crudeoil into their confines. The upper and lower pumping chambers arelikewise provided with outwardly-opening discharge valves 36 and 38,respectively, through which production oil may be forced out of theconfines of the pumping chambers into a discharge passage 40 whichextends upwardly through the upper and lower pumping'sections. The upperend of the discharge passage 40 empties into a collection chamber 42defined in the upper portion of the housing 22 above the upper pumpingsection U.

The upper and lower'bladders 28 and 30 are adapted to be alternatelyexpanded and contracted under the influence of an operating liquidsupplied by a reversible pump 44. This pump 44 may be of the gear, vaneor piston type and is coupled to a reversible three-phase electric motor46. The pump 44 is in communication with the interior of the lowerbladder 30 by means of a first operating liquid passage 48. The interiorof the upper bladder 28 is in communication with the pump 44 by means ofa second operating liquid passage 50. With this arrangement, rotation ofthe electric motor 46 in a first direction will cause one of thebladders 28 or 30 to-be filled while at the same time it will efiect thecollapse of the other bladder. Thereafter, the motor will be operated inthe opposite direction so as to withdraw the fluid from the expandedbladder and pump it into the collapsed bladder so as to effect theexpansion of the previously-collapsed bladder and the concurrentcollapseof the previously-expanded bladder. During the time the bladdersare in a collapsed condition, their inlet valves 32 and 34 willpermitthe entry of production oil into the pumping chambers 24 and 26. Whenthe bladders are expanded, the production-oil contained within thepumping chambers will be expelled therefrom through the discharge valves36 and 38. Since one bladder will always be undergoing expansionwhile-the other is being contracted, this arrangement provides asubstantially continuous flow of production oil that flows upwardlythrough the tubing string 21. An upwardly opening check valve SS-isarranged in the tubing string 21 above thehousing 22.

A pressure relieving unit R is interposed between the pump 44 and theupper end of the operating liquid passages 48 and 50. The purpose ofthis unit is to prevent the imposition of excessive liquid pressuresupon the ininterior of the bladders 28 and 30. The construction andoperation of this pressure relieving unit R isfully set forthhereinafter.

Electric power for the motor 46 is provided by means of a conventionalthree-phase alternator A located at the earths surface. This alternatorA is coupled to a suit able prime mover P by leads 45, 47 and-49, and tothe electric motor 46 by means of three leads 51, 52, and 53 housedwithin a suitable cable 54 in a conventional manner. Control over theelectric current passing through these leads 51, 52 and 53 is eifectedby means of a controller C which may be partially or entirelysurface-located, and the construction and operation of which is fullyset forth hereinafter.

The PumpingUnits U and L More particularly, a detailed showing of theconstruction of the upper and lower pumping units U and L appears inFIGURES 2a, 2b and 20. Referring to these figures and additionally toFIGURES 3 and 4, it will be observed that the upper portion of the firstoperating liquid passage 48 is defined by a vertically extendingpassageway 58 formed through a generally cylindrical upper mandrel 60.The lower end of the passageway 58 receives the upper end of avertically extending pipe 62. 'The pipe 62 extends through the upperpumping chamber 24. The lower end of the pipe 62 is connected to avertically extending passageway 64 formed through a second mandrel 66.The lower end of the passageway 64 is connected to the upper end of apassageway 68 formed in a third generally cylindrical mandrel 70 spacedimmediately below the mandrel 66. The lower end of the passageway 68receives the upper end of a second length of vertically extending pipe72. The latter extends downwardly through the lower pumping chamber 26.The lower portion of the pipe 72 is in communication with the.space.74encompassed by the lower bladder 30-by means of a plurality of openings76. The lower end of the pipe 72 is in communication with a fill passageformed in a lowermost mandrel 82. The lower end of the fill passage 80receives a fill plug 84. Access to this fill plug 84 is provided bymeans of a removable cap 86 that constitutes a closure for the lower endof the housing 22.

As is also indicated in FIGURES 2a, 20, 3, 4 and 5, the upper portion ofthe second operating liquid passage 50 is defined by a verticallyextending passageway 88 expipe 90 that terminates within the space 92encircled by the upper bladder 28, the lower end of this pipe 90 beingopen. Pipe 90 is arranged centrally of the housing 22.

With continued reference to the aforementioned figures, the lower end ofthe discharge passage 40 is defined by a vertically extending passageway94 formed in the lowermost mandrel 82. The lower portion of the lowerpumping chamber 26 below the latters discharge valve 38 is connectedwith the passageway 94 by a plurality of radially extending apertures95. The upper end of this passageway 94 is connected to a pipe 96 thatextends upwardly through the lower pumping chamber 26 parallel with theaforedescribed pipe 72 employed to convey operating liquid to theinterior of the lower bladder 30. As shown in FIGURE 2b, the upper endof the pipe 96 terminates in a passageway 98 formed through the mandrel70. The lower portion of the passageway 98 is in communication with thelower portion of the upper pumping chamber 26 below the lattersdischarge valve 34 by a plurality of radially extending apertures 99.The upper end of the passageway 98 is in communication with a passageway100 formed through the mandrel 66 spaced above the mandrel 70. The upperend of the passageway 108 is in communication with the lower end of apipe 102 that extends through the upper pumping chamber 24 parallel withthe aforedescribed pipe 62 employed to conduct operating liquid to theinterior of the lower bladder. The upper end of the pipe 102 is incommunication with the lower end of a passageway 104 formed in the uppermandrel 60. The upper end of this passageway 104 empties into thecollection chamber 42 encompassing the pressure relieving unit R, thepump 44 and the motor 46.

The Inlet Valves The upper and lower inlet valves 32 and 34 are ofidentical construction and similar parts thereof bear the same referencenumerals in the drawings. With particular reference to FIGURES 2b, 8 and8a, the upper inlet valve 32 includes a flexible band 1-10 formed ofspring steel, or the like, which has its mid-portion afiixed to a rigidmounting ring 112 by a rivet 113. The mounting ring 112 is formed on thecenter portion of a sleeve 114 that is affixed within the housing 22 atthe lower end of the upper pumping chamber 24. The mounting ring 112 iscoaxial with the housing 22 and its outer periphery is of lesserdiameter than the inner periphery of the housing so as to define anannulus 116. The mounting ring 112 is formed with a plurality ofcircumferentially spaced apertures 118 which are radially aligned withapertures 120 formed in the housing 22. An elastic sleeve 122,preferably formed of an oil resistant synthetic rubber, is encompassedby the flexible band 110. The lower end of the sleeve 122 is affixed tothe sleeve 114 by a ring 123.

The flexible band 110 in its relaxed position assumes the retractedshape shown in FIGURE 8. At this time production oil will be free toflow inwardly into the bottom of the upper pump chamber 24 through theapertures 120 and 118. When the upper bladder 28 is expanded, theelastic sleeve 122 and the flexible band 110 will be expanded to theirpositions of FIGURE 8a. In this position, the elastic sleeve 122 willblock inward flow through the apertures 118 and 120. It is important tonote that in this expanded condition, the flexible band 110 willrestrain extrusion of the elastic sleeve 122 into the aperture 118 ofthe ring 112. If such extrusion were permitted to take place, theelastic sleeve would be subject to damage.

The Discharge Valves The outwardly-opening discharge valves 36 and 38are also of identical construction and similar parts bear the samereference numerals. These upper discharge valves 36 and 38 are shownparticularly in FIGURES 2b, 9 and 10. Referring thereto, the upperdischarge valve 36 includes a flexible band 130 formed of spring steelor the like having its mid-portion aflixed to a rigid mounting ring 132by a rivet -134. The mounting ring 132 is formed in the intermediateportion of a sleeve 136 that is rigidly positioned within the housing 22below the aforedescribed sleeve 114. The outer diameter of the sleeve132 is smaller than the inner diameter of the housing 22 so as to definean annulus 138 therebetween. The mounting ring 132 is formed with aplurality of circumferentially spaced apertures 140. A second flexibleband 142 has its mid-portion aflixed to the exterior of the mountingring 132 by the rivet 134. This outer flexible band 142 is arranged inthe same plane as the inner flexible band 130 and may be formed of thesame material. An elastic sleeve 144 encompasses the exterior of themounting ring and flexible band. This elastic sleeve is preferablyformed of an oil-resistant synthetic rubber. The upper end of theelastic sleeve 144 is aflixed to the apper portion of the sleeve 136 bya ring 145.

In their relaxed position, the inner and outer flexible bands 130 and142 will be disposed in their retracted position of FIGURES 2b and 9. Atthis time the upper bladder 28 is shown in its collapsed position. Theelastic sleeve 144 then serves to restrain inward flow of productionfluid through the apertures 140, while the outer flexible band 142prevents the sleeve from being extruded into the mounting ring apertures140 under the influence of well bore pressure. Referring now to FIGURE10, the parts of the upper discharge valve 36 are shown arranged in theposition which they assume when the upper bladder 28 is expanded. Itwill be observed that the exterior surface of the upper bladder has beenexpanded against the inner surface of the inner flexible band 130.

The Pressure-Relieving Unit R The pressure-relieving unit R is shownparticularly in FIGURES 2a and 3 through 7, and referring thereto itwill be noted that this unit is mounted within the upper mandrel 60. Themandrel 60 is formed with a pair of vertically extendingpressure-relieving chambers and 152. As indicated in FIGURE 7, the lowerportion of the passage 150 is in communication with the first operatingliquid passage 48 by means of a transversely extend ing bore 154. A plug156 is provided for the opposite end end of the bore 154. The lower endof the other pressurerelieving chamber 152 is in communication with thesecond operating liquid passage 50 by means of a second transverselyextending bore 158. The opposite end of this port is likewise closed bya plug 160. A11 upwardlyopening ball check 162 is positioned within thepressure relieving chamber 150 above its point of intersection with thebore 154. As indicated in FIGURE 6, a radially extending bore 165connects the pressure relieving chamber 150 with the operating liquidpassage 50 at a point above the ball check 162.

The ball check 162 is constantly biased downwardly by a plunger 164 thatis backed by a coil compression spring 166. The plunger 164 and spring166 are contained within a cylinder 168 which is threadably securedwithin the upper portion of the pressure-relieving chamber 150. Thecylinder 168 is open at its bottom but is provided with an upper closure170. The intermediate portion of the cylinder 168 is formed with a pairof apertures 172. The outer diameter of the cylinder 168 is reduced atthis point so as to define an annulus 174. The annulus 174 is incommunication with a transversely extending passageway 176, as indicatedin FIGURE 4. The opposite end of this passage 176 is in communicationwith an equalizing chamber 178. The outer Wall of this equalizingchamber is defined by a diaphragm 180, preferably formed of anoil-resistant synthetic rubber. A protective metal cover 182 is providedfor the diaphragm 180. The diaphragm and its protective cover are ofannular configuration and their peripheral portions are secured to themandrel 60 by a plurality of bolts 184. One or more apertures 186provide communication between the exterior surface of the diaphragm 180and the collection chamber 42.

A second upwardly-opening ball check 190 is positioned within thepressure relieving chamber 152 above its point of intersection with theradially extending bore 158. As indicated in FIGURE 6, anothertransversely extending bore 192 connects the pressure relieving chamber152 with the operating liquid passage 48 at a point above the ball check190. It will also be observed from FIGURE 6 that the ends of theradially extending ports 165 and 192 are closed by plugs 194 and 196.The ball check 190 is constantly biased downwardly by a plunger 198 thatis backed by a coil compression spring 200. The plunger 198 and spring200 are contained Within a cylinder 202 similar to the aforedescribedcylinder 168 disposed in the chamber 150. The intermediate portion ofthe cylinder 202 is formed with a pair of apertures 204 and the outerdiameter of the cylinder is reduced at this point so as to define anannulus 206. The annulus 206 is in communication with a transverselyextending passageway 208, as indicated in FIGURE 4. The opposite end ofthis passageway 208 is in communication with the aforedescribedequalizing chamber 178.

General Operation of the Upper and Lower Pumping Units U and L In theoperation of the aforedescribed pumping apparatus, it may be assumedthat the pump 44 is first perated in a direction which causes itsdischarge to be pumped downwardly through the operating liquid passage48 into the space 74 encompassed by the lower bellows 30. As indicatedin FIGURE 20, this expansion of the lower bellows 30 will serve to forceproduction oil outwardly through the lower discharge valve 38 throughthe apertures 95 and into the lower end of .the discharge passage 40,.the lower end of the latter being defined by the passageway 94 at thispoint. From the upper end of the passageway 94 the production fluidtravels through thepipe 96 into the passageways 98 and 100 and then intothe upper pipe 162. From the upper end of the pipe 102 .the pumedproduction fluid flows through the passageway 104 into the collectionchamber 42. The production liquid from the collection chamber 42 liftsthe check valve55 and passes upwardly through the tubing stringZl.

During the time the lower bellows 30 is expanded, the upper bellows 28will be maintained in itscollapsed position of FIGURES 2 b and .11.Accordingly, production fluid will be free to flow inwardly through theupper check .valve 32 into the upper pumping chamber 24. Referring toFIGURE 11, it should be particularly noted that the positioning of thepipes 62 and 102 within the pumping chamber 24 affords a rigidsupportabout which the upper bellows 28 may be collapsed. The provisionof this support eliminates any wrinkling of the bladder, whichwrinkling, ifpermitted, would subject the bladder to rapid wear andpossible damage. When the internal pressurization of the lower bladder30 has continued until the pressureexisting therewithin reaches apredetermined magnitude, the controller C will efiect a reversal of themotor 46 in the manner to be described hereinafter. Accordingly, thedischarge of the pump 44 will now be directed into the upper end of theoperating liquid passage 50 while the discharge thereof will be incommunication with the operating liquid passage 48. Accordingly, the.upper bladder 28 will now be expanded and the lower bladder 30contracted. The production fiuid admitted to the upper pumping chamber24 by means of the upper inlet valve 32 will now be expelled outwardlythrough the upper discharge valve 36 so as to pass through the apertures99 and into the portion of the discharge passage 40 defined by thepassageway 100, as indicated in FIGURE 2b. At the same time, the lowerintake valve 34 will admit production fluid into the confines of thelower pumping chamber 26. This operation will continue until thecontroller C again reverses the direction of rotation of the motor 46.

The Controller C of FIGURE 13 Each time one of the bladders 24 or 30reaches a predetermined pressure, the controller C eifects a reversal ofthe motor 46. The controller C therefore senses the time required forthe bladder pressure to reach a predetermined magnitude and then effectsa reversal of the motor 46. As noted hereinabove, the motor 46 is athreephase motor and therefore may be reversed by interchanging two ofthe three leads 51, 52 or 53 through which electrical current issupplied to the motor 46. Upon interchanging two such leads, therevolving magnetic field within the motor 46 is reversed and thedirection of rotation of the motor changes.

Reference will now be had to FIGURE 13 which shows one form which thecontroller C may take to perform the function of interchanging two ofthe connections to the motor 46 when the pressure inone of the bladdersreaches a predetermined level. In thesystem of FIGURE 13, the lead 53 isconnected to two stationary contacts 251 and 252 which are respectivelyassociated with movable contacts 253 and 254. The lead 52 is connectedto stationary contacts 255 and 256 which are also respectivelyassociated with the movable con tacts 253and 254. The movable contact253 is connected to the lead 47, and the movable contact 254 isconnectedto the lead 49. The movable contacts 253 and 254 serve tointerchange the connections between the leads 47 and 49 and the leads 52and 53.

Encirc'ling the lead 49 is a coil 257 which is serially connected with arelay 258. The relay 258 has contacts 259 and 261. The contacts 259 and261 are also mechanically connected to a dash pot 262 which isthreshhold in nature and upon being operated causes the contacts 259 and261 to remain closed until the dash pot discharges a predeterminedamount of fluid, after which the contacts open. The contacts 259 and 261are coupled through a transformer 263 to the leads 47 and 49. Thus,electrical energy may pass from the leads 47 and 49 through thetransformer 263 to the contacts 259 and 261 to be applied to a relay 264which in turn controls the movable contacts 253 and 254.

Consider now that the fcontroller'C as shown in FlG- URE 13 is operatingwithin the system of FIGURE 1 such as to apply electrical energy to themotor 46. Initially assume that themovable contacts are in the positionsshown such that the leads 47 and 52 are connected, and the leads 49 and53 are connected. With these leads so connected assume that the motor 46will rotate in such a direction as to fill the bladder 24. At a timewhen the pressure in the bladder 24 reaches apredetermined level, theload on the motor 46 will increase and slow down the motor causing it todraw an increased amount of electrical current. As increased currentpasses through the motor 46, the current in the leads connecting themotor to the alternator A will increase. The current in the lead 49 istherefore sensed by the coil 257 to determine when the pressure reachesa predetermined level. Upon the occurrence of an increase in current inthe lead49, a voltage is induced in the coil 257, causmg current to flowin the relay 258. The current flow in the relay 258 causes the contacts259 and 261 to close, thereby withdrawing the cylinder in the dash pot262.

With the closure of'the contacts 259 and 261, altermating-currentelectrical energy will pass through the transformer 263, and thecontacts 259 and 261 and energize the relay 264. With the energizationof the relay 264, the movable contacts 253 and 254 will be motivated tothe right to interchange the connections between the leads 52 and 53 andthe leads "47 and 49. The lead 52 is thus connected to the lead 49, andthe lead 53 is connected to the lead 47. With these leads so connectedthe motor 46 will reverse its direction of rotation and the bladderv 30will now be filled. The dash pot 262 will maintain the contacts 259 and261 closed for a period of time set to coincide as nearly as possible,to the time required to fill the bladder 30. After the passage of thistime interval coinciding as nearly as possible to the time required forthe bladder 30 to reach apredetermined pressure, the dash pot 262 willrelease the contacts 259 and 262 thereby de-energizing the relay 264.When the relay 264 is de-energ'ized, the movable contacts 253 and 254will return to the positions in which they are shown, such that lead 47is connected to the line 52 and the lead 49 is connected to the lead 53.The motor 46 is thus again reversed and the cycle is repeated. It maytherefore be seen, that each time the pressure in one of the bladdersreaches a predetermined level the motor 46 is reversed to collapse thefull bladder and inflate the empty bladder. Thereafter, the connectionswill again be interchanged and the direction of rotation of the motor 46will again be reversed.

The Controller of FIGURES 14, 14a and 14b Reference will now be had toFIGURE 14 which 9 shows another form which the controller C may take. Inthe system shown in FIGURE 14, a portion of the controller C is locatedin the well adjacent to the motor 46. This portion of the system is setotf by dashed lines in FIGURE 14.

In the controller of FIGURE 14, the instant when either of the bladders24 or 30 is filled to a predetermined pressure is sensed to reverse themotor 46. The system for sensing the pressure in the bladders 24 and 30in cludes cylinders 271 and 272 which are connected respectively to thespaces 92 and 74, respectively, encompassed by the upper bladder 24 andthe lower bladder 30 by tubes 273 and 274. Positioned inside cylinders271 and 272 respectively are pistons 276 and 277. Springs 278 and 279are mounted respectively within the cylinders 271 and 272 to cause thepistons 276 and 277 to be urged to oppose the hydraulic pressures fromwithin the bladders 24 and 30. Also opposing the pressures within thebladders is the oil pressure from the production column which isconnected to intake ports 281 and 282 respectively of the cylinders 27 1and 272. The pistons 276 and 277 are connected at the extremities of arod 284 which in turn carries magnetic elements 285 and 286. Themagnetic elements 285 and 286 are positioned to be urged into magneticgaps in magnetic cores 287 and 288 respectively. The magnetic cores 287and 288 carry windings 289 and 291, respectively, which are seriallyconnected in the leads 52'and 53, respectively.

The aforedescribed portion of the controller system of FIGURE 14 islocated below the surface in a well adjacent the motor 46. The leads 51,52 and 53 are then brought to the surface to be connected to thesurfacelocated portion of the controller system prior to passing to thealternator A. The lead 51, upon reaching the surface, is connectedthrough one winding 292 of a differential relay 294. The lead 52, afterpassing through the coil 291, is brought to the surface and connectedthrough the other winding 293 of the differential relay 294. From thewinding 293 the line 52 passes to two fixed contacts 295 and 296 in aswitch 297. The line 53, after passing through the winding 292, isconnected to two other stationary contacts 298 and 299 of the switch297. The movable contacts 301 and 302 of the switch 297 are connectedrespectively to the lines 47 and 45.

The two windings 292 and 293 of the differential relay 294 serve tocontrol contacts 303 which are serially connected with a battery 304 anda small switching motor 305. The connection of these elements is suchthat when the contacts 303 are closed by the differential re lay 294,the battery 304 energizes the motor 305. The motor 305' carries aswitching cam 306 which serves to alter the position of the movablecontacts 301 and 302 of the switch 297.

In the operation of the controller as shown in FIG- URE 14 toperiodically reverse the motor 46, an indication that a reversal occuris manifested when either of the pistons 276 or 277 is moved in anupwardly direction. That is, when the pressure within one of thebladders 30 or 24 reaches a predetermined level, one of the pistons 276or 277 in the cylinders 271 and 272 will be moved in an upwardlydirection due to the hydraulic pressure in either the line 273 or theline 274 overcoming the forces exerted by the production column and aspring. When one of the pistons 276 or 277 is so moved, the arm 283 willbe raised thereby moving the magnetic elements 285 and 286 into themagnetic gaps in the cores 287 and 288, respectively. It may thereforebe seen that when the pressure within one of the bladders 24 or 30reaches the predetermined level at which the motor 46 is to be reversed,the air gaps in the magnetic cores 287 and 288 will be diminished'byreason of the magnetic elements 285 and 286 moving into such air gaps.

With the closure of the magnetic circuit of the magnetic cores 287 and288, the windings 289 and 291 will present substantial increasedinductive impedance. Thus the impedance in the lines 52 and 53 issubstantially increased when it is desired to reverse the motor 46. Withthe change of impedance presented to the lines 52 and 53, the electricalcurrent flowing in the lines will be substantially diminished, thuscreating an unbalance between the current flowing through the windings292 and 293 of the differential relay 294. With the occurrence of suchan unbalance, the differential relay 294 will close the contacts 303thereby allowing the battery 304 to energize the motor 305. When themotor 305 is energized, it revolves the cam 306 such as to alter theposition of the movable contacts 301 and 302 of the switch 297. Thealteration in position of the movable contact 301 and 302 willinterchange the connections of the lines 45 and 47 with respect to theleads 52 and 53. With the interchanging of the leads direction ofrotation of the motor 46 will be reversed, thereby relieving thepressure in the full bladder to such an extent as to withdraw themagnetic elements 285 and 286 from the magnetic gaps in the cores 287and 288. The windings 289 and 291 now present greatly reduced impedanceto the current flowing in the lines 52 and 53 with the result thatsubstantially equal current now flows in each of the three lines to themotor 46, and with further result that the current in the diiferentialrelay 294 now becomes balanced, thereby allowing contacts 303 to openand deenergize the motor 305. In this manner, the switch 297 is alteredin position each time the pressure in one of the bladders 24 or 30reaches a predetermined level and the motor is thereby reversed tocomplete the other halfcycle of the operation.

It is to be noted in the system of FIGURE 14 that changeable inductancesare utilized as the changeable impedances in the leads 52 and 53;however, various other changeable impedances might be utilized. Two suchchangeable impedances are shown in FIGURES 14a and 14b. The changeableimpedance of FIGURE 14a includes a resistor 306 which is normallyshunted out by contacts 307 however, when the rod 284 is urgedupwardly-,- the contacts 307 will be opened causing the resistance 306to appear in the lead and present an increase in impedance to thecurrent flowing therein.

With regard to FIGURE 14b, an auto-transformer 305 is shown connectedbetween two of the three leads, e.g. leads 51 and 52. The current in thelead 52 is then passed through one contact 306 of a double contactswitch 307, such that the auto-transformer 305 is normally not effectivein the circuit. However, when the rod 284 is urged upwardly, the movablecontact of the switch 307 breaks the contacts 306 and makes the contact308 such that only a portion of the voltage between the leads 51, 52 isapplied to the motor 46. That is, only a portion of the voltage betweenthe lines is tapped bit from the auto-transformer 305 to be applied tothe motor 46.

It is to be noted in considering the changeable impedances describedabove that only the inductive impedances shown in FIGURE 14 allow thesystem to operate with no switching contact to be located beneath thesurface in the oil wells. A distinct advantage thus exists in favor ofthe inductive impedance as maintenance in this system will be reduced.

In the operation of the system shown in FIGURE 14 it is to be noted thatthe current in the leads 5'1, 52 and 53 will be substantially reducedprior to the time when the switch 297 actually interchanges theconnections between the leads. That is, due to the fact that thechangeable impedances located in the lines 52 and 53 present anincreased impedance to current flowing in the lines, prior to the timewhen its switching operation is to be performed, the current in theselines will be substantially reduced. The current in the line 51 willalso be reduced due to the fact that the electrical current flowing intoand out of any three phase system must always be equal and if current isreduced in two leads it will drop in the third. The result of thisreduction in current prior to the performance of a switching operationis that the switch 297 does not interrupt heavy currents and therefrommay be much smaller. t may therefore be seen, that in the system ofFIGURE 14, two distinct functions are performed, i.e. at the time whenthe reversal of the motor should occur the current flowing to the motoris reduced, then the actual switching operation is performed.

The Controller of FIGURE 15 It is to be noted, that a single changeableimpedance may be utilized in a system similar to FIGURE 14 to provide asignal which will eifectthe necessary switching operation. Such a systemis shown in FIGURE 15. In FIGURE 15, similar parts to parts previouslydescribed with respect to FIGURE 14 carry a like reference numeral. Therod 284 which is urged upwardly each time the fluid pressure within oneof the bladders 24 or 30 reaches a predetermined level is connected to asingle magnetic element 311. The magnetic element 311 is thereby urgedinto a magnetic gap in a magnetic core 312. The magnetic core 312carries a winding which is serially connected in the line 53. The lines52 and 53 are then connected to a diiferential relay 314 which issimilar to the differential relay just as described with reference toFIGURE 14. Connections are then made from the differential relay 314 toa double-pole motoropera-ted cam reversing switch 315 which is similarto the motor-operated switch shown with respect to FIG- URE 14 includingthe switch 297 and the motor 305.

I The operation of the controller shown in FIGURE 15 is quite similar tothat shown in FIGURE 14. At a time when the pressure within one of thebladders 24 or 30 reaches a predetermined level, one of the pistons 276or 277 will be urged upwardly imparting a motion to the arm 283 whichwill cause the rod 284 to move the magnetic element 311 into themagnetic gap of the core 312. When the magnetic element 311 is placed inthe core 312, the magnetic lines of force set up by the winding" 313will be increased thus causing an increased inductance to result for thecoil 313. The increased inductance of the coil 313 thus causes thecurrent in the line 53 to be diminished and different from the currentin the line 52 thereby activating the differential relay 314. Thedifferential relay 314 then serves to reverse the connection between thelines 52 and 53 and the lines 47 and 49 just as was explained withrespect to FIGURE 14.

In the system of FIGURE 15 which employs only a single changeableimpedance, the electrical current is not reduced to the same extentwhich it is reduced in the system employing two changeable impedances.Therefore, the switch 315 in FIGURE 15 has more stringent requirementsthan the switch performing a similar function in FIGURE 14. It maytherefore be seen, that by using only one changeable impedance elementin the oil well, the switching operation performed at the surfacebecomes more difficult. The choice of application between the twosystems as shown in FIGURES 14 and 15 will of course depend upon thecircumstances surrounding the application.

Still another form which may be taken by the controller C of FIGURE 1 isshown in FIGURE 16. In FIGURE 16 the leads 52 and 53 are connected to adouble-pole cam-operated reversing switch 320 similar to the switch 297of FIGURE 14. The leads 51, 52 and 53 are also connected to a smallthree-phase timing motor 317. In the operation of this system of FIGURE16, the period required for the motor 46 to fill one of the bladders 24or 30 to a predetermined pressure is made to coincide to the runningperiod of the reversing timer motor 317. In this manner, the timingmotor 317 which is operated from the same source of power as the motor46 and is thus synchronized, periodically interchanges the connectionsbetween the leads 52 and 53 and the leads 47 and 49 The interval of suchan operation is made to coincide as nearly as possible to the intervalduring which the bladders 24 and 30 are filled to a predeterminedpressure. In the system of FIGURE 16 considerable simplicity exists;however, the operation of the controller C is not directly controlled bythe pressure within the bladders 24 and 30. Therefore, exact synchronismmay not result; however, with the possible existence of reducedefficiency of operation the system of FIGURE 16 operates verysatisfactorily in certain applications.

Operation 0 the Pressure-Relieving Unit R Referring again to FIGURES 1through 7, assuming that the pressure within the lower bladder 30 forexample, should be raised above a desired maximum, the pressurerelievingunit R will serve to effect an automatic release of such pressure. Inthis manner, damage to the bladder from over-stretching will be avoided.The operating liquid pressure existing within the space 74 encompassedby the lower bladder 30 will be communicated to the lower portion of thepressure relieving chamber by the bore 154, as will beclear from FIGURES2a and 7. This pressure tends to lift the ballcheck'162 against thecombined downward force provided by the spring 166 and the productionfluid pressure existing within the collection chamber 42, the latterpressure being communicated to the upwardly-facing surfaces of theplunger 164 through the passageway 176, the end of this passagewayremote from the pressure relieving chamber 150 communicating with thecollection chamber 42. This arrangement permits the use of a smallerspring 166 than would be the case where the upper portionof thepressurerelieving chamber did not exist at the pressure of the pumpedproduction fluid.

Assuming that the pressure within the lower bladder 30 increases to theextent that the ball check 162 is lifted from its seat, the lower end ofthe pressure relieving chamber 150 will be placed in communication withthe operating liquid passageway 50 by means of the passageway 165, aswill be clear from examination of FIGURE 6. In this manner, the excesspressure will be automatically relieved from within the lower bladder30, and communicated to the upper bladder 28. In a similar manner,should the pressure within the space 92 encompassed by the upper bladder28 rise above a predetermined magnitude, the ball check will be liftedoff its seat so as to connect the lower portion of the otherpressure-relieving chamber 152 with the operating liquid passage 48 thatis connected to the lower bladder 30.

Conclusion From the foregoing description it will be apparent that thepresent invention provides an efficient and fool-proof pumping apparatusthat is especially adapted to be utilized in pumping oil wells. Theoperating liquid used for expanding and contracting the bladders iscompletely isolated from the production oil. This is an importantconsideration since sand and other contaminants are often carried by theproduction oil. Although bladders are shown as being the production oilpumping members, other forms of movable well pumping means may beemployed, as for example a bellows, diaphragm or piston. The positioningof the inlet and discharge valves at the lower portion of the pumpingchambers permits sandbearing production oil to be pumped without causingthe pumping chambers 24 and 26 to become filled with sand. Additionally,the positioning of the electric motor 46 above the pumping units U and Lpermits the upwardly flowing production liquid to cool the motor. Theseveral unique controller arrangements for effecting reversal of 13 theelectric motor are both practical and foolproof. Their use eliminatesthe need for the complicated reversing valve mechanisms heretoforeemployed in pumping apparatus of this nature.

It is to be understood that the present invention is not limited to thespecific arrangement of parts described but rather that variousmodifications and changes may be made thereto without departing from thespirit of the invention or the scope of the following claims.

We claim:

1. In a pumping apparatus having a housing, a pumping chamber formed insaid housing and an expansihlecontractile pumping member disposed withinsaid pumping chamber, a valve controlling flow relative to said pumpingchamber, comprising: a rigid mounting ring formed with circumferentiallyspaced apertures; a flexible band in encircling relationship with themajor portion of said mounting ring; and an elastic sleeve coaxial withsaid mounting ring and movable radially into sealing engagementtherewith, said band preventing extrusion of said sleeve into saidapertures.

2. The subject matter of claim 1 further characterized in that saidflexible band is disposed intermediate said ring and said sleeve and inradial alignment with the apertured portions of said ring.

3. The subject matter of claim 1 further characterized in that said bandis formed of a resilient metal.

4. In a pumping apparatus having a housing, a pumping chamber formed insaid housing and an expansiblecontractile pumping member disposed withinsaid pumping chamber, an inlet valve for said pumping chamber,

comprising: a rigid mounting ring affixed to said housing and formedwith circumferentially spaced apertures; a flexible band encircled bythe inner periphery of said mounting ring and having its intermediateportion rigidly affixed to said ring; and an elastic sleeve coaxiallydisposed within said mounting ring and movable radially outwardly intosealing relationship therewith, said band preventing extrusion of saidsleeve into said apertures.

5. In a pumping apparatus having a housing, a pumping chamber formed insaid housing and an elastic bladder disposed Within said pumpingchamber, a discharge valve for said pumping chamber, comprising: a rigidmounting ring aflixed to said housing and formed with circumferentiallyspaced apertures; an inner flexible band encircled by the innerperiphery of said mounting ring and having its intermediate portionrigidly affixed to said ring; said bladder being encompassed by saidband; an outer flexible band encompassing said mounting ring inalignment with said apertures and having its intermediate portionaffixed to said mounting ring; and an elastic sleeve coaxiallyencircling said mounting ring and outer flexible band, said outer bandpreventing extrusion of said sleeve into said apertures and said innerflexible band preventing extrusion of said bladder into said apertures.

6. The subject matter of claim 5 further characterized in that saidinner band is normally biased out of engagement with the aperturedportions of said ring and is yieldably movable into engagement with saidportions to prevent such extrusion.

No references cited.

